This invention generally relates to systems for providing electrical power to electronic devices without a wire or other connection to a power source. It also relates to systems for providing electronic signals to an electronic device without wire connection.
In particular, the invention relates to systems for providing electrical power to flight test equipment externally mounted on an airplane. The overall problem is to provide an improved system for collecting data to satisfy flight test requirements. In an existing system, test wiring is installed in the airplane. Such test wiring typically carries power to test instruments and carries data from those instruments to data recording devices or telemetry transmitters. This wire adds substantial weight to the airplane, which may complicate the test. The installation of wire also requires substantial labor. Furthermore, in accordance with a known technique, holes are drilled in the airplane to provide paths through which to string wires. The system disclosed herein addresses the specific problem of reducing the amount of wiring installed and the number of holes drilled to support a test.
The term “test” as used herein means any operation where an aircraft carries equipment of a temporary nature, often under an experimental airworthiness certificate. A common example is flight test instrumentation where the aircraft itself is the subject of the test. Another example is “captive carry” tests where an airplane carries a component of a missile or spacecraft so it can be easily monitored during a flight and retrieved afterward for repeated tests. A third example is a one-time set of measurements for scientific research or technology experimentation, where initial success with an ad hoc device might lead to later work with more robust installations on the aircraft.
There are several existing solutions: (1) string wires for power and data, and drill holes where needed; (2) use wireless links for data transfer, but continue to use wires to power the instrumentation; and (3) use wireless links for data transfer, but use batteries to power the instrumentation.
The first known solution has the disadvantage that wire adds substantial weight to the airplane. This may complicate the test plan, e.g., by requiring that some equipment be offloaded to meet weight and balance constraints for some tests, then re-installed for other tests. In addition, a wire harness requires substantial labor to design and install before the test program and to remove afterward. Furthermore, holes drilled in the airplane to provide paths through which to string wires must be designed and checked by engineering, approved by the Federal Aviation Administration or the Department of Defense, and then drilled, filled, smoothed, sanded, and inspected. If the flight test aircraft is used after completion of the test program, the holes must be filled after the wires are removed, and then periodically re-inspected and maintained.
The second known solution has the advantage that wireless links can reduce the total number of wires, and therefore somewhat reduce the weight of the added equipment and the labor to install the test equipment. However, holes must be drilled for power cables, even if no data wires accompany them, so this solution does not reduce the hole count as much as the wire count.
The third known solution has the advantage that wireless links with battery-powered instrumentation can substantially reduce both the number of wires and the number of holes. However, the batteries add substantial weight, and they must be replaced or recharged after each test flight. Replacing a battery or attaching a recharge cable typically requires removal and replacement of an access panel, so the labor required is substantial.
There is a need for a solution that avoids the disadvantages of the foregoing existing solutions.